ABSTRACT The automotive sector is going through a phase of stiff competition among various Original Equipment Manufacturers for increasing their profitability while ensuring highest levels of customer satisfaction. The biggest challenge for such companies lies in minimizing their overall cost involving investments in Research and Development, manufacturing, after sales service and warranty costs. Higher warranty costs not only affect the net profit but in turn it also affects the brand image of the company to a large extent in the long run. An effort is made here to target such warranty costs due to frequent tail pinion and hub seal leakages on single reduction/hub reduction axles of Heavy Commercial Vehicles in the field. A preliminary study involving the severity analysis of such failures is followed by a step by step investigation of these failures. Investigation basically focuses on the temperature and internal pressure mapping of the differential in different modes to correlate the seal characteristics with the usage profile. Tests are carried out on two vehicle models having different transmission differential configurations (6×4 and 4×2 respectively). Discussion includes vehicle level test setup and procedure followed to simulate the actual failure pattern during the highway trials in the real user environment. Another set of tests are carried out with the necessary modifications in order to understand the level of improvement made. Finally, recommendations are made based on the comparative study of the results. INTRODUCTION As per the Service and Warranty cost data analysis it was found that frequent pinion seal and hub seal (Oil seal and “O”Ring leakage) failures are one of the major causes of customer dissatisfaction due to higher breakdown time. Not only that, it also contributed substantially to the overall warranty cost to the company. During investigation of the field service data an observation was made that the failure complaints were substantially high in vehicles used under severe off road applications such as mines. However, even the failures on the vehicles used for highway applications cannot be ignored and needs to be studied further for tackling the issue on existing vehicles in field as well as Proto Vehicles under development stage. In order to investigate these failures the present exercise was carried out for mapping the rear axle oil temperature and pressure under different conditions so that the failures may be simulated on Tractor vehicles with 4×2 / 6×4 configurations combined with a trailer and further corrective actions may be suggested to overcome this issue. Eighteen monthly IPTV (Incidences per thousand vehicles) was calculated for various models from the field service data and the results are shown in the graph ( Fig. 1) given below: Note: • Models 1 to 8 and 11 are used as rigid truck for highway applications • Models 9 and 10 are used for mining/earth moving applications • Models 12 to 14 are used as tractor trailer combination for highway applications Investigation of Frequent Pinion Seal and Hub Seal Leakages on Heavy Commercial Vehicles2010-01-2015 Published 10/05/2010 Saurabh Singh Tata Motors, Ltd. Narayan Jadhav, Kamaljeet Nandkeolyar, Shirish Pandav and Pankaj Sali Tata Motors Ltd Copyright © 2010 SAE International doi:10.4271/2010-01-2015Downloaded from SAE International by Univ of California Berkeley, Tuesday, July 31, 2018An IPTV of more than 20 for Vehicles used for mining and earth moving applications shows that such seal failures can easily be attributed to the environmental conditions in which the vehicles operate. Harsh conditions like large amount of dust and high temperature cycles in mining applications are most probably the reasons for such a high failure rate. As is known, drive axle assemblies typically include pinion, ring gear and differential gearing which rotates and churns in a lubricant sump within a sealed housing which, unless relieved, may result in a